The growing of mushrooms is done under controlled conditions for a lengthy period of time. Various standard techniques are known. Some of these techniques are described in U.S. Pat. No. 6,018,906, all of the details of which are incorporated herein by reference thereto. As pointed out, two common techniques for mushroom cultivation are in the use of mushroom beds or shelves and in a tray system. Other methods of growing mushrooms have been the bag system, the ridge bed system and deep trough system. These systems, particularly the bed and the tray systems include two distinct phases. Phase I is generally done outdoors and involves composting the material to be used for cultivating the mushrooms. The compost is then conveyed into a mushroom house and fills the receptacles, such as beds or trays. In general, the compost is then heated to pasteurize the compost and ensure that the compost is free from most mushroom pests and diseases. The pasteurized compost then undergoes a cool down procedure. The pasteurizing step could take up to 14 days and the cool down procedure could take about 3 days. The next operation is the spawning where the compost is inoculated with mushroom mycelia by distributing particulate material colonized with mushroom mycelia (spawn) through the compost. The spawning run might take about 14 to 16 days. Next the colonized compost is covered by a layer of nutrient poor material or casing. The casing layer holds the moisture so that the mycelium must grow through the casing layer. The next step might be considered a flash step which occurs about twenty days after the mycelium breaks through the casing layer. The flash step is the first picking of cultivated mushrooms. Finally, after the mushroom heads break through the casing layer there is a final harvesting of the mushrooms. Reference is also had to U.S. Pat. Nos. 6,073,388 and 5,503,647, all of the details of which are incorporated herein with regard to mushroom growing techniques.
In order to provide the best form of cultivated mushrooms under these controlled conditions it would be desirable if there were some assurance of having the mushroom house in a sterilized condition to prevent outside contamination interfering with the mushroom growth. It has been known in other fields to use ozone as a means of sterilization. The use of ozone in connection with the growing of mushrooms, however, has not heretofore been contemplated. One reason, perhaps is that ozone might be considered to create detrimental aesthetic and health affects if the ozone contacts the mushrooms.
Parent application Ser. No. 11/320,279 discloses providing ozone treatment to a mushroom house by having an ozone generator assembly communicating with ozone distributing structure located within the house or enclosure to feed the ozone into the enclosure and around the mushroom growing receptacles in the enclosure. As disclosed in that application the ozone generator assembly is located externally of the enclosure while the ozone distributing structure within the enclosure communicates with an inlet in the wall of the enclosure and has spaced discharged outlets. The ozone distributing structure also includes a hose within the enclosure mounted at the inlet and communicating with a plenum in the enclosure. The plenum has a heat pump and a blower to facilitate feeding the ozone into a manifold having spaced discharged outlets at spaced locations within the enclosure.
Korean patent KR2005114763A appears to disclose a structure for sterilizing the mushroom culture itself through the use of various materials including ozone which are applied directly into the mushroom culture. As illustrated in that Korean patent an ozone generator communicates with a pipeline having supply pipes that penetrate into seal grooves and the culture containers. In this manner the ozone is supplied directly into the culture containers to penetrate into the culture medium. The drawing apparently also illustrates a reduction catalyst supply, an oxygen generator, a humidifier, an air conditioner and a vacuum pump which are all constructed as part of a single circulating circuit with the ozone generator to connect the pipeline in the control chamber with the pipeline and discharge the material flowing therethrough to go directly into the culture medium. The intent is apparently to treat the spawn whereby not only ozone, but also, for example, a catalyst and oxygen are applied directly into the culture. This disclosure differs significantly from the techniques described in the parent application Ser. No. 11/320,279. In that regard, in the parent application the ozone is fed directly into the general atmosphere in the interior of and throughout the mushroom house since it is the interior of the house which is intended to be sterilized. In contrast with the Korean patent, the ozone is intended to sterilize the culture medium itself and in all likelihood would not be of sufficient quantity to flow through and exit from the culture medium to have any significant sterilizing affect on the atmosphere in the interior of the mushroom house or enclosure.